Pyrolytic-deoxygenation of triglycerides model compound and non-edibleoil to hydrocarbons over SiO₂-Al2O₃ supported NiO-CaO catalysts

Catalytic deoxygenation (DO) of triglycerides-based feeds to diesel-like fuel was investigated over NiO-CaO/SiO₂-Al2O₃ and NiO/SiO₂-Al2O₃ catalysts using semi-batch reactor under partial vacuum and inert N₂ flow. The results showed that the bi-functional catalyst exhibited the highest DO activity with product selectivity toward diesel-like fuel n-(C₁₃–C₂₀). The catalytic process appeared to inhibit the occurrence of side reactions via neutralization of the strong acid sites. On the other hand, DO reaction under inert N₂ flow has improved the deoxygenated product, which demonstrate that N₂ flow condition has effectively removed the decarboxylation/decarbonylation gasses (CO₂/CO) from poisoning the catalyst active sites. The high concentration of strong basic-acid sites of the catalyst is the main reason for increased CC cleavage pathway, while milder acidic sites responsible for CO cleavage pathway. High degree of unsaturated fatty acid in the feedstock has affected adversely the DO of triglycerides by accelerating the catalyst deactivation. The N₂ flow condition, degree of unsaturated fatty acid in the feedstocks, acidity and basicity of the catalysts are important factors to improve DO activity as well as product selectivity

Hydrogen production from wood gasification promoted by waste eggshell catalyst

Bio-hydrogen renowned as a future potential hydrogen source and studies were devoted in developing the efficient way to obtain the hydrogen. Biomass gasification of Azadirachta excelsa wood was carried out with addition of naturally derived CaO catalyst using temperature-programmed gasification (TPG) technique. The reaction (TPG) was performed at 50–1000°C in 5% O2/He with flow rate 10 ml/min, and the product gas evolution (H2, CH4, CO and CO2) was detected by online mass spectrometer. The waste eggshell was chosen as a natural source of CaO, and the effect of catalyst loading was investigated in this study. All the fresh and used catalysts were characterized, and the physicochemical changes of the eggshell were observed through scanning electron microscopy, X-ray fluorescence and X-ray diffraction techniques. Hydrogen yield were increased along with the catalyst loading (20%, 40% and 60%) from 57 to 73%, respectively, compared to the reaction without catalyst. The additions of waste eggshell enhanced the catalytic activity and suppressed CO2 production through CaO absorption property which induced the water gas shift reaction that promotes H2 production at lower temperature

Carbon dioxide sorption by tetradecylamine supported on silica gel

Carbon dioxide emissions generated from fossil fuel-based power plants and other industries has reached 400 ppm in atmosphere. This negatively impact the environment, infrastructures and wildlife in particular. A lot of efforts are needed to produce CO2 gas sorbent in order to reduce high CO2 concentration. Therefore, porous silica gel (SG) is modified with amine compound for carbon dioxide capture. Calcinated silica gel functionalized with tetradecylamine (TDA) using wet impregnation has been developed as a porous media. The prepared sorbents is characterized by N2 physisorption technique Brunauer-Emmet-Teller analysis (BET). Significant changes in physical properties of the sorbents further ascertained the dispersion of TDA on the internal channels and external surface of the SG. Reactivity of porous sorbent towards CO2 was evaluated using isothermal CO2 adsorption desorption technique. This study shows 65TDA/SG enable to adsorb CO2 in the highest capacity which is 23.22 cm3CO2per gram sorbent. Moreover, CO2 capture consists of two type sorption which are physisorption and chemisorption. 55TDA/SG is the best sorbent in capturing CO 2by chemisorption (19.62 cm3CO2per gram adsorbent)

CO2 capture on NiO supported imidazolium-based ionic liquid

CO2 capture on NiO supported imidazolium-based ionic liquid, NiO/[emim][HSO4]/SiO2 as an adsorbent was investigated using gas adsorption analyzer and physicochemical properties of the adsorbent were characterized using X-ray powder diffraction (XRD), surface area analyzer (BET method) and temperature-program-desorption analysis (TPD). Immobilization of ionic liquid on silica, [emim][HSO4]/SiO2 slightly decreased the surface area compared to bare silica from 266 to 256 m2/g due to the pore blocking by the confinement of IL in SiO2 pore. Interestingly, introduction of NiO on supported ionic liquid, NiO/[emim][HSO4]/SiO2 was increased the surface area as well as pore volume from 256 to 356 m2/g and 0.14 to 0.38 cm3/g, respectively. The enhancement of surface area and pore volume was significantly increased the CO2 adsorption performance with capacity of 48.8 mg CO2/g adsorbent compared to [emim][HSO4]/SiO2 27.3 mg CO2/g adsorbent)

XRD and CO2 adsorption studies of modified silica gel with octadecylamine

Porous surface of silica gel (SG) have been modified with long and straight chain fatty amine compounds (octadecylamine, ODA) via wet impregnation process. Initially, heat treatment with various temperature which are 100 ºC, 200 ºC, 400 ºC and 600 ºC was done to the SG before continuing with impregnation process. Characterizations by XRD of the treated samples were showed no significant difference in each diffractogram. The best temperature for heat treatment was 600 ºC (SG600) and it was referred to the ability of the SG600 type adsorbents in adsorbing CO2 resulted from adsorption desorption isotherm of CO2. The 5 and 35 wt% of ODA supported on the SG600 was further characterized using XRD analysis which displayed the increasing intensity of crystalline ODA with higher percent amine loaded and shifting of the several crystalline peaks of ODA verified the interaction of SG600-ODA. These further strengthen the dispersion of ODA on the surface of SG600

Characterizations and application of supported ionic liquid [bmim][CF3SO3]/SiO2 in CO2 capture

Supported ionic liquid (IL) [bmim][CF3SO3] on SiO2 was prepared, characterized and its potential evaluated for CO2 capture via adsorption and desorption studies using gas adsorption analyzer. The physical and chemical properties were determined using N2 adsorption/desorption and CO2-TPD analysis. The increasing IL loading caused a drastic decrease in the surface area as well as pore volume due to the confinement of IL within the micropore and mesopore area. However, the increasing IL loading increased the basicity of the sorbent which significantly enhanced CO2 chemisorption. Supported [bmim][CF3SO3] on SiO2 revealed the physical and chemical adsorption of CO2 and resulted in a remarkable CO2 adsorption capacity at atmospheric pressure and room temperature (66.7 mg CO2/gadsorbent) which has great potential in industrial applications

Comparative adsorption isotherm for Beryllium oxide/Iron (III) Oxide toward CO2 adsorption and desorption studies

Surface modification of Fe2O3 by adding BeO was synthesized and calcined at different temperatures of 200-600 °C. The adsorbents were characterized by using XRD, N2 adsorption-desorption isotherm prior to performing CO2 adsorption and desorption studies. The CO2 adsorption data were analyzed using adsorption isotherm models such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. BeO/Fe2O3-300 that calcined at 300 °C showed the most efficient adsorbent with physisorption and chemisorption were measured at 5.85 and 45.88 mg/g respectively. The CO2 adsorption notably best fitted with Freundlich isotherm with R2 = 0.9897 and calculated adsorption capacity closest to experimental data. This implies the CO2 adsorption process was governed by multilayer adsorption on the heterogeneous surface of the adsorbent. The mean free energy of adsorption (E=3.536 kJ/mol) from Dubinin-Radushkevich and heat of adsorption (bT=3.219 kJ/mol) from the Temkin model support that the adsorption process is physical phenomena

Production of biodiesel from waste cooking oil via deoxygenation using ni-mo/ac catalyst

Waste cooking oil (WCO) from palm oil is one of the most prospective biodiesel feedstock when compared to other oil seeds. Thus, WCO has great potential as a green source of diesel fuel for engines in motor vehicles and machinery. This project aimed to study the potential of three randomly selected types of WCO, namely; sample A (used 1× once to fry an egg), sample B (used 3 – 5× to fry salted fish), and sample C (used repeatedly to fry banana fritter) for the production of green diesel fuel over Ni-Mo/AC (nickel and molybdenum oxides incorporated with activated carbon) catalyst through the deoxygenation (DO) process. The prepared catalyst was characterized through X-ray diffraction (XRD), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM). The DO process was performed at 350 ◦C to remove oxygen from the WCO samples. The liquid products were analysed by gas chromatography-mass spectrometer (GC-MS) and gas chromatography-flame ionization detector (GC-FID), to measure the yields of straight-chain hydrocarbons and fractions in the range C8 - C20. Results showed that the highest n-(C8 - C20) hydrocarbon fractions were produced in the order of sample B (89.93%) > C (88.84%) > A (82.81%)

Evaluation of NiO/TALC catalytic performance in carbon dioxide reforming of methane

A series of NiO/Talc (Talc = talcum) catalysts with various Ni loadings (5–15 wt%) has been synthesised via the wet impregnation method and utilised for dry reforming of methane (DRM). All catalysts showed promising catalytic DRM performance and 10%NiO/Talc was found to be the most effective catalyst with 98% CH4 and 80% CO2 conversion respectively (SH2 = 65%; H2/CO close to ⁓1.2) at 700 °C reaction temperature under 1 atm pressure reaction condition. This finding confirmed that excellent DRM activity was corroborated with the high surface area, good NiO dispersion, good basic properties, excellent reducibility and formation of the Mg2Ni phase. The DRM increased with reaction temperature, whereas 700 to 800 °C showed the most optimum activity. The 10%NiO/Talc catalyst appears to have longer a lifetime (highly stable) with low coke affinity. This is confirmed by the high and consistent (CH4 & CO2) conversion with moderate carbon formation (20 wt%) over 10 h reaction time

The influence of calcination temperature on iron oxide (α-Fe2O3) towards CO2 adsorption prepared by simple mixing method = Kesan suhu pengkalsinan ferum oksida (α-Fe2O3) disediakan melalui kaedah campuran ringkas terhadap penjerapan CO2

Synthesized iron oxide, α-Fe2O3 used for CO2 capturing was prepared by a simple mixing method and calcined at temperatures in a range of 350 – 850 °C. CO2 adsorption isotherms at 25 °C and 1 atm found that the sample namely s450 that calcined at 450 °C gave the highest CO2 adsorption activity with the adsorption capacity of 17.0 mgCO2/gadsorbent. Monodentate carbonate, bidentate carbonate and bicarbonates formation were observed on s450 through the IR spectra. The basicity of s450 was identified by chemisorption of CO-TPD which contains weak, medium and strong basic sites with CO total adsorbed amount of 1.99 cm3/g. It was found that s450 calcined at 450 °C has certain crystallite peaks that abruptly increased through the XRD diffractogram. The texture properties of s450 generated high porosity and more uniform sphere shape particle size with high surface area (50.5 m2/g). Furthermore, it is composed of trimodal distribution for pore size distribution curve desirable for CO2 adsorption. Penjerapan CO2 terhadap ferum oksida, α-Fe2O3 yang disintesis melalui kaedah campuran ringkas dan dikalsin pada suhu 350- 850 °C. Penjerapan isoterma CO2 pada suhu bilik, 25 °C and 1 atm mendapati sampel s450 yang dikalsin pada suhu 450 °C menunjukkan aktiviti penjerapan CO2 paling tinggi dengan keupayaan penjerapan sebanyak 17.0 mgCO2/gpenjerap. Spektrum IR telah membuktikan pembentukan spesis monodentat karbonat, bidentat karbonat dan bikarbonat pada s450. Sifat bes s450 yang dikenalpasti menggunakan jerapan kimia CO-TPD dimana jumlah CO yang dijerap oleh tapak bes lemah, sederhana dan kuat adalah 1.99 cm3 /g. Difraktogram XRD pula menunjukkan terdapat beberapa puncak kekisi yang meningkat. Tekstur s450 pula mempunyai keporosan yang tinggi dan bentuk sfera yang lebih sekata serta luas permukaan yang tinggi (50.5 m2 /g). Tambahan lagi, graf taburan saiz liang s450 juga terdiri daripada taburan jenis trimodal yang menjadi salah satu faktor penting dalam penjerapan CO